Speaker of the House vs. Senate Majority Leader

Here's something I don't understand - everytime a new topic comes up, Pelosi's opinion is considered the ultimate. But isn't Harry Reid, the incoming Senate Majority leader, just as powerful or even more powerful? I know the Speaker of the House is technically third in line to the presidency, but in terms of actual dutes isn't the leader of the Senate even more powerful than the leader of the House?

To clarify, it's only the spending bills that start in the House. The Senate introduces and handles lots of crap before the House.

Fenian's right about the power. The Senate has standing rules for debate, an orderly procedure that's the same for each bill. (That's why there's a filibuster in the Senate, but not in the House.) Meanwhile, in the House, the Rules Committee decides the rules for each debate, so there's a lot more control over how things are debated/presented/lubed up. The Speaker can bully the House into his or her agenda. Hastert was quite effective at this (especially with DeLay at his side). Meanwhile, Bill Frist, because he couldn't manipulate the rules, was about as ineffectual as [insert witty analogy here].